Wash the lettuce thoroughly and cut it into bite-sized pieces.
Blanch the bean sprouts in boiling water for 2 minutes, then rinse with cold water.
Drain the oil from the canned tuna and lightly stir-fry it to remove any fishy smell.
Place the lettuce, bean sprouts, and tuna on top of the rice in order.
Finish by drizzling soy sauce, sesame oil, and sprinkling sesame seeds on top.